The present invention relates to an ink jet head having a plurality of nozzles for discharging ink supplied from an ink supply part. For example, it relates to an ink jet head suitable for use in a print head of an ink jet printer, a manufacturing method therefor and a printer including the ink jet head.
An ink jet printer is of a type injecting ink droplets through the use of an ink jet head having a plurality of nozzles to discharge the ink droplets toward a recording medium such as printing paper for directly adhering them thereonto. For example, the printing to the printing paper is made in a manner that, in a state where the ink jet head is reciprocated in cross directions of the printing paper, the printing paper is conveyed in a direction perpendicular to the moving directions of the ink jet head.
FIG. 34 is an exploded perspective view showing an essential construction of a conventional ink jet head. As FIG. 34 shows, the conventional ink jet head is equipped with a head plate 310 having a plurality of (ten in FIG. 34) of ink discharging sections 312 made therein and is made to be connected to an ink tank 320.
The ink tank 320 holds ink internally and supplies the ink through an ink supply port 322 to the head plate 310.
Each of the ink discharging sections 312 made in the head plate 310 is equipped with a nozzle for discharging ink, and is provided with an ink pressure chamber to be filled up with ink for each nozzle and an ink pressurizer for pressurizing the ink within the pressure chamber, with ink droplets being discharged from each of the nozzle when each of the ink pressurizers pressurizes the ink pressure chamber.
Incidentally, for example, as this ink pressurizer, a bimorph laminated member is known which is composed of a piezoelectric element such as piezo and a diaphragm.
In addition, a common ink passage, not shown, is formed in the interior of the head plate 310, and the ink discharging sections 312 communicate through ink supply passages (not shown) with this common ink passage in a branched configuration.
Still additionally, an ink supply port 313 is made in the head plate 310 and communicates with the common ink passage.
Yet additionally, the head plate 310 and the ink tank 320 are coupled to each other in a manner that an adhering portion 311 of the head plate 310 and an adhering portion 321 of the ink tank 320 are adhered to each other through an adhesive or the like, and at this time, an ink outlet 322 of the ink tank 320 and the ink supply port 313 of the head plate 310 communicate with each other.
With this construction, the ink held in the ink tank 320 is supplied through the ink outlet 322 and the ink supply port 313 to the common ink passage and further delivered from the common ink passage through each of the ink communicating passages to the pressure chamber of each of the ink discharging sections 312.
In each of the ink discharging sections 312, the ink is injected from the nozzle with the pressure chamber being pressurized by the ink pressurizer, thus accomplishing the printing to printing paper.
However, in such a conventional ink jet head, an adhesive or the like is applied to the adhering portion 311 of the head plate 310 and the adhering portion 321 of the ink tank 320 and they are joined to each other for the adhesion between the head plate 310 and the ink tank 320, and hence, there is a possibility that, at this adhesion, the adhesive is forced out from adhering portions 311 and 321 to interfere with the electrodes of the ink discharging section 312 to affect the operations thereof adversely.
Therefore, in manufacturing the ink jet head, there is a need to secure a sufficient distance (adhesion allowance) between the adhering portion 311 and the ink discharging section 312 on the head plate 310, which hinders the enhancement of integration of the head plate 310, thereby making it difficult to achieve the size reduction of the head plate 310, that is, the ink jet head (in its turn, the ink jet printer)
Moreover, the head plate 310 generally has a low rigidity, in particular, in a case in which the head plate 310 is composed of a laminated substrate using a thin-film piezo as a piezoelectric element, its thickness is as low as approximately 0.2 mm, and for this reason, a problem arises in that the head plate 310 is breakable, particularly, in the process of the adhesion of the ink tank 320 to the head plate 310 or other processes, so the handling thereof requires the great care.
The present invention has been developed in consideration of these problems, and it is therefore an object of the present invention to improve the degree of integration of the head main body through the use of a worked-out construction for achieving the size reduction of an ink jet head and the size reduction of a printer as well, and further to secure a sufficient rigidity of the head main body.
For this purpose, in accordance with the present invention, there is provided an ink jet head having a plurality of nozzles for discharging ink supplied from an ink supply part, characterized by comprising a head main body including a plurality of pressure chambers each provided for each of the nozzles and filled up with ink, a plurality of pressurizers each provided for each of the pressure chambers for pressurizing the pressure chamber to discharge the ink in the pressure chamber through the nozzle and ink supply passages for supplying the ink from the ink supply part to the plurality of pressure chambers, and a joint section formed on the head main body to protrude therefrom for joining the ink supply part to the head main body, with the head main body being formed on a substrate and the substrate is partially removed from the head main body to form, in the substrate, a communicating passage for making a communication between the ink supply passage and an ink supply port of the ink supply part, and the joint section being formed as a residual portion of the substrate on the head main body.
Furthermore, in accordance with the present invention, there is provided a method of manufacturing an ink jet head having a plurality of nozzles for discharging ink supplied from an ink supply part, characterized by comprising a step of forming, on a substrate, a head main body including a plurality of pressure chambers each provided for each of the nozzles and filled up with ink, a plurality of pressurizers each provided for each of the pressure chambers for pressurizing the pressure chamber to discharge the ink in the pressure chamber from the nozzle and ink supply passages for supplying the ink from an ink supply part to the plurality of pressure chambers, and a step of removing the substrate partially from the head main body to form, in the substrate, a communicating passage for making a communication between the ink supply passage and an ink supply port of the ink supply part and of forming the residual portion of the substrate on the head main body as a joint portion for joining the ink supply part to the ink main body.
Still furthermore, in accordance with the present invention, there is provided a printer equipped with an ink jet head having a plurality of nozzles for discharging ink supplied from an ink supply part, characterized by comprising a head main body including a plurality of pressure chambers each provided for each of the nozzles and filled up with ink, a plurality of pressurizers each provided for each of the pressure chambers for pressurizing the pressure chamber to discharge the ink in the pressure chamber from the nozzle and an ink supply passage for supplying the ink from the ink supply part to the plurality of pressure chambers, and a joint section formed on the head main body to protrude therefrom for joining the ink supply part to the head main body, with the head main body being formed on a substrate and the substrate is partially removed from the head main body to form, in the substrate, a communicating passage for making a communication between the ink supply passage and an ink supply port of the ink supply part, and the joint section being formed as a residual portion of the substrate on the head main body.
As advantages, this enables securing a sufficient rigidity of the head main body and the ink jet head as well, and eliminates the need for the direct connection of the ink supply port of the ink supply part to the head main body, and further, even in the case of adhering the ink supply part through an adhesive or the like to the head main body, eliminates the possibility of the forced-out adhesive sticking to the pressurizers of the head main body, which results in eliminating the need for the formation of an adhesion allowance on the head main body, enhancing the degree of integration, and achieving the size reduction of the ink jet head and the printer as well.
In addition, since the ink supply part is joined to the head main body through the use of a portion (residual portion) of the substrate used in the process of manufacturing the head main body, it is possible to manufacture the ink jet head easily and at a low cost to reduce the manufacturing cost.
Still additionally, since, even in a case in which the ink supply part is adhered to the head main body through the use of an adhesive or the like, there is no possibility of the forced-out adhesive being attached to the pressurizers and others of the head main body, not only the formation of an adhesion allowance on the head main body becomes unnecessary and the integration becomes improvable, but also the size reduction of the ink jet head becomes feasible.
Yet additionally, the pressurizer can be composed of a diaphragm constituting a portion of the pressure chamber and a piezoelectric element for pressurizing the pressure chamber by driving this diaphragm, which enables the certain construction of the pressurizers and the improvement of facilitation of manufacturing of the ink jet head.
Moreover, the substrate can be made of magnesium oxide, which permits certain and easy manufacturing of the head main body and reduces the manufacturing cost because of the improvement of facilitation of manufacturing of the ink jet head.
Still moreover, the substrate can be partially removed through photoetching treatment, which allows the certain and easy removal of the substrate, thus reducing the manufacturing cost because of the improvement of facilitation of manufacturing of the ink jet head.